1. Field of the Invention
The present invention relates to a low magnetic chemical mechanical polishing conditioner, and more particularly to a chemical mechanical polishing conditioner formed by abrasive particles with low magnetic contents.
2. Description of Related Art
Chemical mechanical polishing (CMP) is a common polishing process in various industries, which can be used to grind the surfaces of various articles, including ceramics, silicon, glass, quartz, or a metal chip. In addition, with the rapid development of integrated circuits, chemical mechanical polishing becomes one of the common techniques for wafer planarization because it can achieve an object of whole planarization.
During the chemical mechanical polishing process of semiconductor, impurities or uneven structure on the surface of a wafer are removed by contacting the wafer (or the other semiconductor elements) with a polishing pad and using a polishing liquid if necessary, through the chemical reaction and mechanical force. When the polishing pad has been used for a certain period of time, the polishing performance and efficiency are reduced because the debris produced in the polishing process may accumulate on the surface of the polishing pad. Therefore, a conditioner can be used to condition the surface of the polishing pad, such that the surface of the polishing pad is re-roughened and maintained at an optimum condition for polishing. In the process for manufacturing a conditioner, it is necessary to dispose an abrasive layer by mixing abrasive particles and a binding layer on the substrate surface, and to fix the abrasive layer to the surface of the substrate by brazing or sintering methods.
Besides, in the process for manufacturing these abrasive particles, these abrasive particles have magnetic property due to frication or collision; however, diamonds with magnetic property will be attracted iron debris produced in the copper process, thereby influencing quality of abrasive particles. Therefore, it is necessary to screen the abrasive particles on the chemical mechanical polishing conditioner to obtain the abrasive particles without magnetic property, in order to maintain an optimum condition for polishing. In present technology, a magnetic separator is used to adsorb and remove substances with magnetic property, when materials pass through the magnetic separator; the substances with magnetic property are adsorbed by a magnetic bar to accomplish an effect for screening substances with magnetic property. Besides, in present technology, there is another method for screening substances with magnetic property is also used, in which a dry magnetic separator is used to purify and classify diamonds to remove diamonds with magnetic property.
In the known technology, such as Taiwan Patent Issue No. 204632, it discloses that a belt conveyor consists of the belt which is wound around a driving roller at one end and is wound around the nonmetallic cylindrical body at the other end and a rotary magnet which is alternately magnetized to N poles and S pole at the circumferential edge. This rotary magnet is rotated in the same direction at the rotating speed higher than the rotating speed of the cylindrical body, by which the nonmagnetic metallic refuse component are discharged from the other end of the belt in the locus different from the locus of the refuse components of the other components. The refuse components are thereby separated. The driven roller is disposed with the deviation further outward from the above-mentioned other end below the cylindrical body and the belt is wound around this roller as well. Consequently, the damaging of the belt is prevented even if the refuse such as washers or such iron scrap having edges resembling the shapes thereof exists in the refuse.
Besides, in the other known technology, such as China Utility Model Patent Issue No. 202155258U, it discloses a dry magnetic separator for purification, selection and grading of ultra-hard materials, which comprises a frame, a magnetic roll, a magnetic roll adjusting mechanism, a casing and a driving motor. A feeding bin is arranged at the top of the casing and communicated with the casing through a discharging port, a non-magnetic material bin and a magnetic material bin are disposed on the lower portion of the casing, a separation split tip is arranged at the joint of the non-magnetic material bin and the magnetic material bin, and a scraper is arranged on one side of the separation split tip. The dry magnetic separator can better realize industrial production of purifying and grading of weak-magnetic ultra-hard materials such as artificial diamond, cubic boron nitride and the like, and has the advantages of convenience in use, stability and reliability in quality of separated products and the like.
However, a magnetic field gradient method or a magnetic track method and so on are mainly used to screen diamonds in the above-mentioned known technology, in order to screen and separate metallic or inorganic particles with magnetic property or non-magnetic property. However, the abrasive particles through above-mentioned screening method and screening results are not necessarily to chemical mechanical polishing conditioner. Therefore, there is an urgent need for a screening method adequate for a chemical mechanical polishing conditioner, which can be used to screen and remove particles with magnetic property included in abrasive particles before manufacturing the conditioner to obtain abrasive particles with low magnetic contents adequate for the chemical mechanical polishing conditioner, and the chemical mechanical polishing conditioner with low magnetic property is manufactured and formed by the abrasive particles with low magnetic contents to improve magnetic attracting questions between the magnetic abrasive particles and abrasive debris or abrasive impurities, thereby maintaining the polishing performance of the chemical mechanical polishing conditioner.